A port container, also known as a CASK, is a large, sealed container used to transport goods by sea. It is typically made of metal and is designed to be waterproof and airtight. The term 'CASK' comes from the Old French word 'casque', meaning 'BOX'. Casks are commonly used to transport liquids, such as oil, wine, and beer, but can also be used to transport other goods. They are an important part of the shipping industry, as they allow for the safe and efficient transportation of goods across the world.